“Heat assisted magnetic recording,” optical assisted recording or thermal assisted recording (collectively hereinafter HAMR), generally refers to the concept of locally heating a recording medium to reduce the coercivity of the recording medium so that an applied magnetic writing field can more easily affect magnetization of the recording medium during a temporary magnetic softening of the recording medium caused by the local heating. HAMR allows for the use of small grain media, which is desirable for recording at increased areal densities, with a larger magnetic anisotropy at room temperature assuring a sufficient thermal stability. HAMR can be applied to any type of storage media, including for example, tilted media, longitudinal media, perpendicular media, and/or patterned media.
HAMR heads utilize various optical articles in order to direct and concentrate energy for heating the recording medium. These optical articles often include features, such as gaps, trenches and gratings that are formed within the waveguide of HAMR heads. Typical etching processes could benefit from changes that afford stricter control of feature size.